Flexible Heat Pipe

ABSTRACT

A flexible metal heat pipe coated or covered with a layer of plastic material to provide the heat pipe the flexibility required in a process to bend the heat pipe without damaging the heat pipe due to over-concentrated stress at a particular section of the heat pipe.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention is related to a heat pipe, and more particularly, to a flexible heat pipe that is covered with a layer of plastic material to permit flexibility by a summary bending device or by manual in bending the heat pipe.

(b) Description of the Prior Art

A heat pipe is a very practical super conducting device in executing rapid heat transfer. To cope with different space requirements, the heat pipe permits it to be curved and/or flattened.

Internal construction of the heat pipe contains a capillary structure to execute transfer by a work fluid in liquid state. At where it is bent or flattened, the capillary structure is vulnerable to be deformed due to that the wall of the pipe is elongated or compressed. Therefore, the expected function of the capillary structure is compromised. To minimize destructive effect to the capillary structure, the bending and flattening processes are done by the genuine maker according to the finalized dimension; and it is difficult to make minor modification at the customer's end.

SUMMARY OF THE INVENTION

The primary purpose of the present invention is to provide a flexible heat pipe to allow readjustment at the customer's end without affecting heat transfer property of the heat pipe to significantly improve flexibility of the application of the heat pipe.

To achieve the purpose, a heat pipe of the present invention is coated or covered with a plastic material tightly attached to the outer wall of the heat pipe to take advantage of its plastic elasticity property in avoiding non-arc deformation at where the bending takes place due to over-concentrated stress when the heat pipe is bent for readjustment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a preferred embodiment of the present invention.

FIG. 2 is a schematic view showing a tool generally used to bend a heat pipe.

FIG. 3 is a schematic view showing a clamping device of the bending tool for a heat pipe.

FIG. 4 is a schematic view showing a heat pipe finished with the bending process.

FIG. 5 is a schematic view showing changes to the present invention before and after the bending process.

FIG. 6 is a schematic view showing a flexible heat pipe (round pipe) of the present invention.

FIG. 7 is a schematic view showing a flexible heat pipe (flat pipe) of the present invention.

FIG. 8 is a schematic view showing another preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a heat pipe 12 is connected to a heating block 20 and a heat sink 25 to provide optimal heat transfer. The heat pipe is bent according to the spatial requirements of a system where the heat pipe is installed. In the prior art, the bending process is done at a genuine manufacturer using a special clamping device to execute readjustment of direction of the angle. As illustrated in FIG. 2, the heat pipe to be bent is secured by means of a clamping device 31 and a stationary roller 32; though a central point of the stationary roller 32 is fixed, the stationary roller 32 is capable of revolving. In the bending process, a mobile roller 33 travels following an arc route with its size adjustable as desired while keeping a constant distance form the stationary roller 32. The clamping device, the stationary roller, the mobile roller, and a clamping surface of the heat pipe are all processed with an arc as illustrated in FIG. 3 to ensure of close contact with the heat pipe by permitting the heat pipe to keep its circular section shape.

Now referring to FIG. 4, a straight round heat pipe 12 completed with primary process is then processed with a dedicated clamping device to be bent into a finished product 121. Using improper clamping device or bending by manual fails to achieve tight holding of the heat pipe for uniform distribution of force applied, resulting in over-concentrated stress at a particular section. Consequently, curvature of the heat pipe 122 changes to produce either too small or wild inner and outer curvatures to compress internal space of the heat pipe, non-circular cross section at where bending takes place, serious damage to the capillary structure, and heat transfer efficiency of the heat pipe.

In the bending process, wall of the heat pipe must be supported and covered up in the clamping device to prevent non-arc curvature changes due to over-concentration of force applied. An outer wall of the heat pipe 12 of the present invention is tightly coated with a layer of plastic material 14 containing Teflon, PU, PP, nylon, rubber, resin, or a plastic compound as a primary composition that delivers plasticity and flexibility at the same time. Upon bending the heat pipe, the coated layer tightly wrapping up the heat pipe causes the heat pipe to be confined. The coating material gives a specific thickness that functions as a clamping device to keep changes in arc direction and area to the minimum, and achieve uniform distribution of stress to avoid over-concentration of force applied while maintaining a specified rounded surface and arc curvature. As illustrated in FIG. 5, the heat pipe made of metal material becomes a support structure to the plastic coating thus to maintain a finished shape. In the bending process, it takes only a summary curvature indicator, and manual adjustment is feasible to bend the heat pipe to a proper curvature and form as required.

To facilitate tight attachment of the plastic material to the heat pipe merely completed with a normal manufacturing process, a surface of the heat pipe is roughened by using a sandblasting, plating or other chemical erosion method, and is then coated with the plastic material by means of mold injection, hot melting, cast polishing, and casting mold tools. To improve adhesion strength between the coated layer and the metallic body of the heat pipe, a solidified adhesive or other adhesive paste may be sprayed on the surface of the heat pipe. However, two sections respectively of vaporization and condensation where must be maintained with the optimal heat transfer contact of the heat pipe are not coated with the plastic material.

A round heat pipe as illustrated in FIG. 6, is coated with a layer of the plastic material saving both of the vaporization and condensation sections to achieve flexible bending for readjustment either by using of a summary bending tool or by manual.

Similarly, a flat heat pipe is coated with a layer of the plastic material saving both of the vaporization and condensation sections to achieve flexible bending for readjustment either by using of a summary bending tool or by manual as illustrated in FIG. 7.

On the aspect of heat dissipation of the heat pipe, the heat pipe, the heating block, and the heat sink are integrated in one piece, meaning it is impossible to change their relative locations. As the market of DIY combination is getting popular, the function of heat sink is provided in a module, e.g., a water-cooling heat dissipation unit that is connected with a flexible hose to the heating block and the heat dissipation member for supplying heat dissipation required by the system. Compared to the water-cooling method, heat dissipation achieved by phase change of a work fluid delivers a heat transfer efficiency approximately 540 times greater than that provided by a single phase liquid heat transfer from using the water cooling method; furthermore, the work principle of phase changes does not depend on support equipment of a pump helps cost reduction; however, changes in flexibility are not as good as the method of arrangement of pipeline. To improve flexibility of the heat pipe, the present invention as illustrated in FIG. 8 allows an end user to selectively connect heat pipes between the heating block and the heat sink to meet the heat dissipation function for the system with an overall efficacy better than that provided by the water-cooling heat dissipation system.

The prevent invention provides a structure of a heat pipe to improve a bending process for adjusting the heat pipe and flexibility of the application of the heat pipe, and the application for a patent is duly filed accordingly. 

1. A flexible heat pipe with a metal outer wall thereof tightly coated or covered with a layer of plastic material; a plasticity of the coated layer wrapping up and confining the heat pipe to function as best supportive mold in bending and adjusting curvature of the heat pipe; and a metallic structure of the heat pipe supporting the plastic layer coated on the heat pipe to maintain a final shape of the heat pipe.
 2. The flexible heat pipe as claimed in claim 1, wherein curvature and shape of the flexible heat pipe is adjusted by a summary bending device or by manual.
 3. The flexible heat pipe as claimed in claim 1, wherein a vaporization section and a condensation section of the heat pipe are not coated with the layer of plastic material for both sections to maintain their optimal heat transfer contact.
 4. The flexible heat pipe as claimed in claim 1, wherein the layer of the plastic material has Teflon, PU, PP, nylon, rubber, resin, or a plastic compound that delivers plasticity and elasticity at the same time.
 5. The flexible heat pipe as claimed in claim 1, wherein, a method to coat the layer of the plastic material is applicable to a round or a flat heat pipe, and also applicable to a heat pipe which wick structure is groove, mesh, fiber, powder sintering or any combination of them without affecting the existing property of the heat pipe.
 6. The flexible heat pipe as claimed in claim 1, wherein, a surface of the heat pipe is roughened by using a sandblasting, plating or any other chemical erosion method and is tightly coated with the plastic material by using injection molding, hot melting, cast polishing, and casting mold tools.
 7. The flexible heat pipe as claimed in claim 1, wherein, a solidified adhesive or other adhesive paste is sprayed on the surface of the heat pipe to improve adhesion strength between the coated layer and the metallic body of the heat pipe.
 8. The flexible heat pipe as claimed in claim 1 wherein, the heat pipe allows final shaping at a customer's end and is available in module to improve flexible application of the heat pipe. 